Protéines nucléaires basiques et croissance chez l'hypocotyle de Lupinus albus L.

Summary Characteristic changes in the basic nuclear proteins/DNA ratio may be observed during the residual growth of lupine seedling hypocotyls.This ratio decreases at the very beginning of hypocotyl growth (growth initiation) but increases during its active growth. A second decline coincides with gemmule development. No further increase in the relative amount of basic proteins can be observed during the diminishing elongation before growth ceases.These results may be related to the known regulating action of the gemmule on hypocotyl growth.     

The Nature and Duration of Gene Action for Vernalization Response in Wheat

Four near-isogenic lines of wheat were studied to determinethe nature and duration of gene action for vernalization responseunder 2 weekly vernalization periods from 0 to 10 weeks. With time to floral initiation the Vrn 1 Vrn 2 and Vrn 1 vrn2 genotypes showed a cumulative response whereby days to floralinitiation decreased as the period of vernalization increased.The vrn 1 Vrn 2 and the vrn 1 vrn 2 genotypes also showed acumulative response for periods of vernalization less than 6weeks for the former and 8 weeks for the latter. Days to earemergence was closely related to days to floral initiation dueto the constancy of the period from floral initiation to earemergence across all lines and treatments and, consequently,they gave similar measures of the relative strength of vernalizationresponse. It appears that genes for vernalization response ceaseto act after floral initiation. The implications of these findings to breeding for increasedadaptability and yield in wheat are discussed. Triticum aestivum, wheat isogenic lines, vernalization, floral initiation, ear emergence, gene action     

Effect of lateral suppressor on petal initiation in tomato

Flowers developing on tomato ( Lycopersicon esculentum ) plants homozygous for the lateral suppressor ( ls ) mutation lack petals. Scanning electron micrographs revealed that in ls plants no second whorl organs were initiated. The initiation of first, third, and fourth whorl organs were unaffected by this mutation. To investigate interactions between the cells in different layers of the floral meristem during organ initiation, a periclinal chimera between wild-type and ls tomato was generated. Flowers of the chimera having ls cells in the outer meristem layer (L1) and wild-type cells in internal layers (L2 and L3) developed normally, including the initiation of organ primordia that differentiated as petals in normal positions within the second whorl. L1 of the chimera developed in a non-autonomous manner during petal development. Thus, wild-type cells occupying the internal meristem layers provided developmental cues necessary for initiation of petal primordia at appropriate positions on the floral meristem. L1 cells carrying the lateral suppressor mutation were fully capable of responding to this information and differentiated appropriately.     

Maternal behaviour of free-ranging sows during the first 8 days after farrowing

The maternal behaviour of free-ranging domestic sows was studied. The sows were observed continuously during 1–2 h periods randomly distributed between 0730 and 1930, from farrowing to the 8th day. The behaviour parameters considered and the general experimental layout were the same as ones used in a previous study. In order to more precisely evaluate possible differences of behaviour between the outdoor and the indoor condition, this new study did not reveal great differences in maternal behaviour. Over time, the sows increased initiation and termination of nursing episodes, with no statistical difference between the sows' behaviour. There was a trend to reduce the variability of the behaviour repertoire over post-farrowing days. This may be the result of the sows' freedom of action and their ability to display the natural behaviours. The implications of environmental conditions on behaviour are discussed.     

The role of prostaglandins for the coordination of myometrial forces during labour

Systematic studies using a superfusion technique for recording myometrial contractility in vitro have been conducted in our department to explore whether prostaglandins (PG) have a differential action on the different segments of the pregnant uterus and also whether the qualitative and quantitative response undergoes a change during spontaneous labour. Myometrial specimens were excised from the fundal area and from the lower uterine segment at elective caesarean section in the 39th week of pregnancy before commencement of labour and at acute caesarean section during ongoing labour. Before labour PGF2 alpha was without or had a very weak effect on upper segment preparations but was stimulatory on lower segment specimens. PGE2 and PGI2 generally induced a biphasic dose-dependent response (stimulation followed by inhibition). During spontaneous labour PGF2 alpha and PGE2 always stimulated upper segment preparations while the contractile activity of specimens from the lower segment was inhibited by PGE2, PGF2 alpha was generally without effect. PGI2 had the same biphasic action before as during labour. With all reservations for the validity of in vitro experiments, the results favour the hypothesis that initiation of labour in the human involves a qualitative shift in the myometrial reactivity to prostaglandins. These alterations may involve suppression of expulsive forces and perhaps some tightening of the lower uterine segment during pregnancy. Following initiation of labour there is a marked increase in the excitatory action of both PGE2 and PGF2 alpha in the fundal area while the lower uterine segment reacts in a way that favours dilatation.     

The effect of a single dose of aflatoxin B1 on the value of nucleolar index of blood lymphocytes and on histological changes in the liver, bursa Fabricii, suprarenal glands and spleen in ducklings

The value of the nucleolar index of blood lymphocytes, as well as histopathological changes in liver, bursa Fabricii, suprarenal glands and spleen in ducklings administered per os a single dose of 1.5 micrograms aflatoxin B1 on the second day of their life, were observed for two weeks. There was a clear correlation observed between morphological changes in the lymphatic system organs and liver and the value of the nucleolar index of peripheral blood lymphocytes on the 13th and 14th day after administration of aflatoxin B1. The results obtained point to different susceptibility of the tested organs and lymphocytes to the action of aflatoxin B1.     

Application of Zinc,Iron and Boron Enhances Productivity and Grain Biofortification of Mungbean

Deficiencies of essential vitamins, iron (Fe), and zinc (Zn) affect over one-half of the world’s population. A significant progress has been made to control micronutrient deficiencies through supplementation, but new approaches are needed, especially to reach the rural poor. Agronomic biofortification of pulses with Zn, Fe, and boron (B) offers a pragmatic solution to combat hidden hunger instead of food fortification and supplementation. Moreover, it also has positive effects on crop production as well. Therefore, we conducted three separate field experiments for two consecutive years to evaluate the impact of soil and foliar application of the aforementioned nutrients on the yield and seed biofortification of mungbean. Soil application of Zn at 0, 4.125, 8.25, Fe at 0, 2.5, 5.0 and B at 0, 0.55, 1.1 kg ha⁻¹ was done in the first, second and third experiment, respectively. Foliar application in these experiments was done at 0.3% Zn, 0.2% Fe and 0.1% B respectively one week after flowering initiation. Data revealed that soil-applied Zn, Fe and B at 8.25, 5.0 and 1.1 kg ha⁻¹, respectively, enhanced the grain yield of mungbean; however, this increase in yield was statistically similar to that recorded with Zn, Fe and B at 4.125, 2.5 and 0.55 kg ha⁻¹, respectively. Foliar application of these nutrients at flower initiation significantly enhanced the Zn contents by 28% and 31%, Fe contents by 80% and 78%, while B contents by 98% and 116% over control during 2019 and 2020, respectively. It was concluded from the results that soil application of Zn, Fe, and B enhanced the yield performance of mungbean; while significant improvements in seed Zn, Fe, and B contents were recorded with foliar application of these nutrients.     

德国鸢尾‘常春黄’花芽分化的形态观察及两种代谢产物的动态变化

鸢尾是世界著名观赏花卉,为研究其花芽分化期的形态和生理指标变化情况,我们以德国鸢尾两季花品种‘常春黄’（Iris germanica cv. Lovely Again）为材料,运用扫描电镜（SEM）观察了德国鸢尾‘常春黄’的花芽分化过程。结果表明：整个形态分化过程可分为6个阶段：花序原基分化期、外轮花被分化期、雄蕊分化期、内轮花被分化期、雌蕊分化期、髯毛形成期。结合上述形态分化过程,分别取其二次花花芽分化时期的顶芽、根茎和叶片部位,以蒽酮比色法测定可溶性糖,以考马斯亮蓝G-250法测定蛋白质含量。结果表明：可溶性糖在花序原基分化的初始阶段含量最高,且在3个部位的含量大小关系始终是：根茎﹥叶片﹥顶芽;蛋白质含量呈先上升后下降的趋势,蛋白质含量的峰值出现于花序伸展初期。     

Energy transduction during catalysis by Escherichia coli DNA photolyase.

Native DNA photolyase from Escherichia coli contains 1,5-dihydroFAD (FADH2) plus 5,10-methenyltetrahydropteroylpolyglutamate. Quantum yield and action spectral data for thymine dimer repair were obtained by using a novel multiple turnover approach under aerobic conditions. This method assumes that catalysis proceeds via a (rapid-equilibrium) ordered mechanism with light as the second substrate, as verified in steady state kinetic studies. The action spectrum observed with native enzyme matched its absorption spectrum and an action spectrum simulated based on an energy transfer mechanism where dimer repair is initiated either by direct excitation of FADH2 or by pterin excitation followed by singlet-singlet energy transfer to FADH2. The quantum yield observed for dimer repair with native enzyme (phi Native = 0.722 +/- 0.0414) is similar to that observed with enzyme containing only FADH2 (phi EFADH2 = 0.655 +/- 0.0256), as expected owing to the high efficiency of energy transfer from the natural pterin to FADH2 [EET = 0.92]. The quantum yield observed for dimer repair decreased (2.1-fold) when the natural pterin was partially (68.8%) replaced with 5,10-CH(+)-H4folate (phi obs = 0.342 +/- 0.0149). This is consistent with the energy transfer mechanism (phi calc = 0.411 +/- 0.0118) since a 2-fold lower energy transfer efficiency is observed when the natural pterin is replaced with 5,10-CH(+)-H4folate (EET = 0.46) (Lipman & Jorns, 1992). The action spectrum observed for 5,10-CH(+)-H4folate-supplemented enzyme matched a simulated action spectrum which exhibited a small (5 nm) hypsochromic shift as compared with the absorption spectrum (lambda max = 385 nm).(ABSTRACT TRUNCATED AT 250 WORDS)     

Mechanistic limitations in the synthesis of polyesters by lipase-catalyzed ring-opening polymerization

Lipase-catalyzed polymerization of caprolactone (CL) in toluene with methoxy-poly(ethylene glycol) (MPEG) and water as initiators was characterized in detail for mechanistic insight. (1)H NMR analysis of polycaprolactone chains (PCL), dicaprolactone, degree of esterification of MPEG, and fractions of PCL chains initiated by MPEG and water were used to follow the reactions. The data were analyzed with the kinetic scheme involving formation of the acylenzyme and its consequent reaction with MPEG, water, or PCL to yield the MPEG- or water-initiated PCL chains, or increase in PCL length. A limit for MPEG initiator esterification in lipase-catalyzed CL polymerization was observed and was explained by preferential reaction of PCL propagation over MPEG esterification at long reaction times and low MPEG concentrations. Slower monomer conversion in concentrated monomer solutions was explained by decreased partitioning of PCL between the solvent and the enzyme. This effect resulted in inhibition of the lipase by the reaction product, PCL chains, and/or insufficient diffusion of monomer to the enzyme active site. High monomer/initiators ratio in these solutions did not yield longer polymer chains due to decreased monomer conversion and the corresponding decrease in product yields; lower yields were also observed for chain initiation by MPEG and water. A shift in the reaction rate-limiting step from formation of acylenzyme in dilute CL solutions to its deacylation in concentrated CL solutions yielded higher PCL polydispersity due to increased initiation by water. Enhanced intramolecular cyclization was also observed. Endgroup composition of PCL chains was influenced by the concentration of monomer, ratio of initiators (MPEG and water), and reaction time, yielding PCL chains initiated exclusively by MPEG at "infinite reaction times."     

Evolution of the sensitivity of isolated adipocytes of ewes to the antilipolytic action of adenosine during pregnancy and lactation

Four successive biopsies of omental adipose tissue were performed on the 43rd, 100th, 140th days of pregnancy and during the 3rd week of lactation in 6 "Pré-Alpes" ewes. Using incubated isolated adipocytes, we studied the evolution of the antilipolytic effect of adenosine. Adenosine presented a significant inhibitory effect on basal lipolysis only at the end of pregnancy. The antilipolytic effect of adenosine on the stimulated lipolysis by a beta-agonist (isoproterenol 400 nM) increased during pregnancy. The maximal effect was observed 1 week before parturition. The level of inhibition remained high during lactation. The lipolytic effect of adenosine-deaminase was enhanced during pregnancy and lactation and evolved similar to the observed action of adenosine. Results suggest that the antilipolytic action of adenosine may have a physiologic importance.     

Electrical properties of developing rat heart. Effects of dexamethasone

Action potentials recorded from perinatal rat ventricles exhibited a plateau (phase 2), followed by a rapid repolarization characteristics of all mammalian ventricular cells. Within the second postnatal week, a number of distinct changes occurred in the contour of action potentials. An early slow depolarization, at the foot of the action potential, preceded the beginning of phase zero. The early slow depolarization was observed until day 12 and disappeared by day 13. A second slow depolarization occurred during the terminal phase of the rapid upstroke of the action potential, persisted through day 13 and disappeared by day 14. On day 12, what had been a homogeneous contour of action potentials seen during the first week converted into a heterogeneous contour. Occasionally, action potentials similar to those recorded from Purkinje fibres in adult heart were recorded from hearts as young as 12 days. By day 14, signs of a spike (the hallmark of action potentials from adult heart) were apparent in some fibres. Treatment of newborn rats with dexamethasone on the second day after birth prevented the disappearance of the second slow depolarization. In adult and aged rat hearts, dexamethasone treatment induced a slow depolarization and a plateau in the region of overshoot. In view of the time-dependent change of the second slow depolarization it is suggested that this phase of the action potential is influenced by the levels of circulating glucocorticoid in developing heart and by changes in calcium sensitivity observed in this species. Heterogeneity of action potentials observed on day 12 postnatal may precede structural differentiation of myofilaments.     

Genetic divergence and biology of adaptation inCicer arietinum L.

Summary The role of 19 structural, developmental and biochemical traits in relation to specific adaptation was analysed in a set of 17 diverse lines with quantified adaptation, representing contemporary cultivars and land races of chickpea (Cicer arietinum L.), using multivariate analysis. Significant varietal variation was observed for most characters, particularly for the activity of the enzyme nitrate reductase (NR) and protein content in the plant. The distance analysis (D²-statistic) revealed that seed size and pod number and their associated attributes were important forces of divergence. The additional forces of divergence were NR activity at the flower initiation stage, yield components such as number of primary and secondary branches, and other features such as plant habit and duration of flowering. The principal component analysis revealed some similarities and also differences from the distance analysis. Leaf size, days to flower initiation, seed size and, to some extent, NR activity at flower initiation stage, were important in the first vector. Developmental traits such as chlorophyll depth, NR activity at the pod initiation and grain filling stages, and the percent protein content in the plant at flower initiation were important in the second vector. In general, the clustering pattern was not related to the geographical origin, seed colour, size of regression coefficient for yield, or deviation from linearity. The importance of the developmental and biochemical attributes in the divergence of cultivated chickpea, such as days to flower initiation, duration of flowering, NR activity and the rates of protein accumulation in developing seeds, and in adaptation, suggests the critical role of these attributes. NR activity at the flower initiation stage would appear to have a major role in the domestication of this crop and its intra-specific differentiation, as an increased seed size could not have been possible without better nutrient uptake and utilization.Part of dissertation submitted for Ph. D. Degree in genetics at the Post Graduate School, I.A.R.I., New Delhi in 1979, by R. G. Dani     

Periodic formation of the oriC complex of Escherichia coli.

We examined formation of an oriC-membrane complex through the chromosome replication cycle by dot-blot hybridization using an oriC plasmid as a probe. In a wild-type culture synchronized for chromosome replication, oriC complex formation was observed periodically and transiently corresponding to the replication initiation event. Prior to initiation of replication the oriC complex was recovered in the outer membrane fraction as well as at the time of initiation of replication. Moreover, periodic formation of the oriC complex was observed even when further initiation of replication was suppressed by culturing an initiation ts mutant at the restrictive temperature. Similar periodic formation of the oriC complex was also observed when DNA elongation was inhibited by addition of nalidixic acid to the culture. However, the second periodic peak did not appear when rifampicin or chloramphenicol was added. Cells which formed the oriC complex at the restrictive temperature could immediately initiate chromosome replication when the cells were transferred to the permissive temperature. We conclude that the oriC region of Escherichia coli forms a specific complex periodically just before and at the time of initiation of chromosome replication and that oriC complex formation is a prerequisite for initiation of chromosome replication.     

Effect of planting dates and maize hybrids on the infestation with sorghum shootfly,Atherigona soccata Rondani and its effect on the yield

Abstract

Twenty maize hybrids plus local were tested for their susceptibility to major pests of sorghum shootfly, Atherigona soccata Rondani under field conditions at Sohag governorate during three planting dates (20th April, 20th May and 5th July) sown during two tested years (2004 and 2005 seasons). The investigation showed that when the sowing dates were considered irrespective of the different years or the maize hybrids it was evident that during the first planting date (20th April), the maize hybrids harboured the highest levels of infestation with sorghum shootfly, Atherigona soccata Rondani. The second planting date (20th May) was the least affected while the third planting date (5th July) received moderate levels of infestation. Results also showed that the average infestation of Atherigona soccata during both seasons was a significantly negative correlation affected by the sowing dates and maize hybrids. The yield of maize hybrids negatively correlated with percentage of infestation by Atherigona soccata. The highest yield obtained from the maize hybrids was slightly infested by Atherigona soccata and sown during the planting date of 20th May. Therefore, the second sowing date (20th May) may be recommended as a proper cultivating date for maize hybrids as it brought about reduction not only in infestation but was also a good method to reduce chemical control. Our results indicated that none of the maize hybrids evaluated were found to be resistant to Atherigona soccata attack but maize hybrids were significantly different in their susceptibility and less than of a local control to the infestation with Atherigona soccata and divided into four groups, the first one was highly susceptible including Giza Baladi; the second group was susceptible including ten maize hybrids namely, Hf 155, Bionear 3062, Bionear 30k8, Nagah 18, Watania 4, HC 326, HC 327, Nafratity, Watania 1 and Bionear; the third group was low resistance including six maize hybrids namely, Hf 122, Hf 123, Hf 129, Hc314, Hc 325 and Hc 352; while the fourth group included Hf 10, Hf 124, Hc 311and Hc 324 and moderately resisted the Atherigona soccata infestation. These may serve as a good material for growing in the areas where the pest is a problem.     

Can the agricultural AquaCrop model simulate water use and yield of a poplar short‐rotation coppice?

We calibrated and evaluated the agricultural model AquaCrop for the simulation of water use and yield of a short‐rotation coppice (SRC) plantation with poplar (Populus) in East Flanders (Belgium) during the second and the third rotation (first 2 years only). Differences in crop development and growth during the course of the rotations were taken into account during the model calibration. Overall, the AquaCrop model showed good performance for the daily simulation of soil water content (R² of 0.57–0.85), of green canopy cover (R² > 0.87), of evapotranspiration (ET; R² > 0.76), and of potential yield. The simulated, total yearly water use of the SRC ranged between 55% and 85% of the water use of a reference grass ecosystem calculated under the same environmental conditions. Crop transpiration was between 67% and 93% of total ET, with lower percentages in the first than in the second year of each rotation. The observed (dry mass) yield ranged from 6.61 to 14.76 Mg ha^?1 yr^?1. A yield gap of around 30% was observed between the second and the third rotation, as well as between simulated and observed yield during the third rotation. This could possibly be explained by the expansion of the understory (weed) layer; the relative cover of understory weeds was 22% in the third year of the third rotation. The agricultural AquaCrop model simulated total water use and potential yield of the operational SRC in a reliable way. As the plantation was extensively managed, potential effects of irrigation and/or fertilization on ET and on yield were not considered in this study.     

Effects of Different Pretreatment on Three Endogenous Hormones Contents and Peroxidase ctivity in Barley Anther

Endogenous hormones (ABA, IAA, IPA) contents and peroxidase activity during the mannitol and cold pretreatment periods were measured in two varietion ("Igri' and "Har- rington' ) barley (Hordeum vulgate L. ) anther. The results were as follows: Firstly, anther endogenous hormone contents were identical changes in both varieties during mannitol pretreatment period. The endogenous hormone contents of anthers were rapidly increased during the early period of pretreatment, reaching their maximum at the first 12 h or the 1st day. After then. the contents began to reduce until they reached a stable level. The result suggested that combined effect of some endogenous hormones, including ABA, was essential for changing the developmental pathway of pollen. Secondly, similar changes in peroxidase activity during the period of mannitol pretreatment were seen in both barley varieties. The activity of peroxidase was remarkably increased during the early period of pretreatment, being highest at the 3rd day. After that, it was reduced from the 3rd day to the 5th day, but increased again from the 5th day to the 7th day. Finally, there were two peaks of peroxidase activity during the cold pretreatment period, which were at the 2nd day and the 14th day for "Harrington' or the 5th day and the 21st day for "Igri'. The second peak was higher than the first one. A second increase in the peroxidase activity for both genotypes were observed from the 28th day to the 35th day during the cold pretreatment period as this phenomenon was in concert with that of mannitol pretreatment.